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Process for preparing mefenamic acid

A technology of mefenamic acid and sodium mefenamic, which is applied in the preparation of organic compounds, chemical instruments and methods, antipyretics, etc., can solve the problems of low productivity and high production cost, and achieve productivity improvement, production cost reduction, and product quality. low yield effect

Active Publication Date: 2009-07-08
BAOJI TIANXIN PHARM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, the traditional synthesis of mefenamic acid is prepared by condensation of sodium o-chlorobenzoate and 2,3-dimethylaniline in the aqueous phase, and its product productivity is low and the production cost is high.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] 1. Preparation of crude mefenamic acid: add 80 ml of dimethyl sulfoxide, 400 ml of petroleum ether, 130 g of o-chlorobenzoic acid, 106 g of sodium carbonate, and 120 g of 2,3-bis 1 gram of methylaniline and copper powder, heat to reflux and separate water, and finish when no water is released, to obtain sodium mefenate, cool the reaction mixture to below 70°C, slowly add industrial hydrochloric acid dropwise with stirring, and adjust the pH to 1~ 2. For example, adjust the pH to 1.5, divide the water layer, wash with 150ml×3 water three times, then cool to room temperature and filter to obtain the crude mefenamic acid.

[0019] 2. Preparation of the finished mefenamic acid: Put half of the crude mefenamic acid obtained above into 200 ml of N,N-dimethylformamide, heat to clear, add activated carbon for heat preservation and decolorization, filter to remove the activated carbon, and cool the filtrate Crystallize at room temperature, filter, wash the filter cake with a small a...

Embodiment 2

[0021] 1. Preparation of crude mefenamic acid: The preparation of crude mefenamic acid is the same as in Example 1;

[0022] 2. Preparation of the finished mefenamic acid: Put the other half of the crude mefenamic acid obtained above into 500 ml of water, and heat it to 70-80°C, for example, to 75°C, and add sodium hydroxide dropwise to adjust the pH to 7-8 For example, adjust the pH to 7.5, stir to dissolve, add activated carbon to keep the decolorization, filter to remove the activated carbon, adjust the pH of the filtrate to 1-2 with hydrochloric acid, for example, adjust the pH to 1.5, cool to room temperature to crystallize, filter, and wash the filter cake with a large amount of water. After vacuum drying, 80 grams of mefenamic acid product was obtained.

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PUM

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Abstract

The invention belongs to the technical field of anti-inflammatory drug production, and relates to a method for preparing mefenamic acid. The method comprises: adding o-chlorobenzoic acid and 2,3-dimethylaniline into a system which is formed by a non-protonic polar solvent and a dehydrant, performing condensation reaction in the presence of an acid-binding agent, a catalyst and a phase-transfer catalyst, and obtaining mefenamic sodium; acidifying the mefenamic sodium and obtaining coarse mefenamic acid products; and refining the coarse mefenamic acid products in an organic solvent and water and obtaining finished mefenamic acid products. The method improves the production efficiency of the mefenamic acid and reduces the production cost of the mefenamic acid.

Description

Technical field [0001] The invention relates to the technical field of production of anti-inflammatory drugs, and more specifically, to a method for preparing mefenamic acid. Background technique [0002] Mefenamic acid, also known as mefenamic acid, acetaminophen and so on. It is a non-steroidal anti-inflammatory drug that can inhibit the synthesis of prostaglandins, inhibit proteolytic enzymes, stabilize the protein structure of cell membranes, and interfere with tissue metabolism. The anti-inflammatory effect of mefenamic acid is stronger than that of clofenac and flufenamic acid. Mefenamic acid is used for the treatment of rheumatism, rheumatoid arthritis, dysmenorrhea, headache, toothache, neuralgia, muscle pain, and post-operative and other inflammatory pain. [0003] However, the traditional mefenamic acid synthesis is prepared by the condensation of sodium o-chlorobenzoate and 2,3-dimethylaniline in the water phase, and its product productivity is low and the production c...

Claims

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Application Information

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IPC IPC(8): C07C229/58C07C277/08A61P29/00
Inventor 章根宝范卫东夏财联
Owner BAOJI TIANXIN PHARM CO LTD
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